Coherence has been perceived to perform an important role in laser therapy comprising laser bio-modulation, laser bio-stimulation, etc. Studies have shown that a highly coherent laser in some cases is more effective than light emitting diodes (LEDs) or other type of lasers which have lower degree of optical coherence. The previously disclosed laser therapy apparatus merely uses whatever laser that is available. For example, semiconductor laser diodes (LDs) are typically used due to their low cost and commercial availability. These lasers have various degrees of optical coherences which may not be optimized for a particular modality or effectiveness associated with the treatment of a particular tissue type or body part. In addition, their optical coherence property can change with ambient conditions such as temperature, optical delivery systems, etc. This coherence change can induce unpredictable treatment results.
Furthermore, continuous scanning scheme of the laser beam is generally employed in the prior arts, in which the effect of intensity gradient created by speckle or interference is diminished due to overlapping by multiple paths within relative short time gaps.
There thus exists a need for a laser therapy apparatus with controlled optical coherence to produce a consistent and optimized therapeutic result.